A superconducting quantum information processor with high qubit connectivity

TL;DR

This paper proposes a novel superconducting quantum processor architecture that enhances qubit connectivity by integrating four-wave mixing in a resonator chain, enabling efficient virtual gate operations with improved coherence.

Contribution

It introduces a new architecture combining four-wave mixing with resonator chains to achieve high qubit connectivity and virtual gate operations in superconducting quantum processors.

Findings

Design maintains nonuniform mode frequencies for virtual gates

System supports multiple resonators within single mode approximation

Enhances qubit connectivity and coherence in superconducting systems

Abstract

Coupling of transmon qubits to resonators that serve as storage for information provides alternative routes for quantum computing. Such a scheme paves the way for achieving high qubit connectivity, which is a great challenge in cQED systems. Implementations either involve an ancillary transmon's direct excitation, or virtual photon interactions. Virtual coupling scheme promises advantages such as the parallel, virtual gate operations and better coherence properties since the transmon's decoherence effects are suppressed. However, virtual gates rely on nonuniform frequency separation of the modes in the system and acquiring this feature is not a straightforward task. Here, we propose an architecture that incorporates the four-wave mixing capabilities of the transmon into a chain of resonators coupled collectively by qubits in between. The system, consisting of numerous resonators all operating within the single mode approximation, maintains the above-mentioned nonuniformity by accommodating different resonators with appropriate frequencies.